User's Manual

Installing and Setting Up the CMC 49
Understanding the Redundant CMC Environment
You can install a standby CMC that takes over if your primary CMC fails.
Failovers can occur when you:
•Run the RACADM cmcchangeover command. (See the cmcchangeover
command section in the
Dell Chassis Management Controller
Administrator Reference Guide
.)
•Run the RACADM
racreset command on the active CMC. (See the
racreset command section in the Dell Chassis Management Controller
Administrator Reference Guide
.)
• Reset the active CMC from Web interface. (See the
Reset CMC option
for
Power Control Operations that is described in "Executing Power
Control Operations on the Chassis.")
• Remove the network cable from the active CMC
• Remove the active CMC from the chassis
• Initiate a CMC firmware flash on the active CMC
• Primary CMC is no longer functional
NOTE: In the event of a CMC failover, all iDRAC connections and all
active CMC sessions will be lost. Users with lost sessions must reconnect to
the new primary CMC.
About the Standby CMC
The standby CMC is identical to and is maintained as a mirror of the active
CMC. The active and standby CMCs must both be installed with the same
firmware revision. If the firmware revisions differ, the system will report as
redundancy degraded.
The standby CMC assumes the same settings and properties of the
primary CMC. You must maintain the same firmware version on both CMCs,
but you do not need to duplicate configuration settings on the standby CMC.
NOTE: For information about installing a standby CMC, see the Hardware Owner’s
Manual. For instructions on installing the CMC firmware on your standby CMC,
follow the instructions in "Installing or Updating the CMC Firmware."